1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Driver for the Conexant CX25821 PCIe bridge
4 *
5 * Copyright (C) 2009 Conexant Systems Inc.
6 * Authors <shu.lin@conexant.com>, <hiep.huynh@conexant.com>
7 * Based on Steven Toth <stoth@linuxtv.org> cx23885 driver
8 */
9
10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12#include <linux/module.h>
13#include <linux/i2c.h>
14#include "cx25821.h"
15
16static unsigned int i2c_debug;
17module_param(i2c_debug, int, 0644);
18MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");
19
20static unsigned int i2c_scan;
21module_param(i2c_scan, int, 0444);
22MODULE_PARM_DESC(i2c_scan, "scan i2c bus at insmod time");
23
24#define dprintk(level, fmt, arg...) \
25do { \
26 if (i2c_debug >= level) \
27 printk(KERN_DEBUG "%s/0: " fmt, dev->name, ##arg); \
28} while (0)
29
30#define I2C_WAIT_DELAY 32
31#define I2C_WAIT_RETRY 64
32
33#define I2C_EXTEND (1 << 3)
34#define I2C_NOSTOP (1 << 4)
35
36static inline int i2c_slave_did_ack(struct i2c_adapter *i2c_adap)
37{
38 struct cx25821_i2c *bus = i2c_adap->algo_data;
39 struct cx25821_dev *dev = bus->dev;
40 return cx_read(bus->reg_stat) & 0x01;
41}
42
43static inline int i2c_is_busy(struct i2c_adapter *i2c_adap)
44{
45 struct cx25821_i2c *bus = i2c_adap->algo_data;
46 struct cx25821_dev *dev = bus->dev;
47 return cx_read(bus->reg_stat) & 0x02 ? 1 : 0;
48}
49
50static int i2c_wait_done(struct i2c_adapter *i2c_adap)
51{
52 int count;
53
54 for (count = 0; count < I2C_WAIT_RETRY; count++) {
55 if (!i2c_is_busy(i2c_adap))
56 break;
57 udelay(I2C_WAIT_DELAY);
58 }
59
60 if (I2C_WAIT_RETRY == count)
61 return 0;
62
63 return 1;
64}
65
66static int i2c_sendbytes(struct i2c_adapter *i2c_adap,
67 const struct i2c_msg *msg, int joined_rlen)
68{
69 struct cx25821_i2c *bus = i2c_adap->algo_data;
70 struct cx25821_dev *dev = bus->dev;
71 u32 wdata, addr, ctrl;
72 int retval, cnt;
73
74 if (joined_rlen)
75 dprintk(1, "%s(msg->wlen=%d, nextmsg->rlen=%d)\n", __func__,
76 msg->len, joined_rlen);
77 else
78 dprintk(1, "%s(msg->len=%d)\n", __func__, msg->len);
79
80 /* Deal with i2c probe functions with zero payload */
81 if (msg->len == 0) {
82 cx_write(bus->reg_addr, msg->addr << 25);
83 cx_write(bus->reg_ctrl, bus->i2c_period | (1 << 2));
84
85 if (!i2c_wait_done(i2c_adap))
86 return -EIO;
87
88 if (!i2c_slave_did_ack(i2c_adap))
89 return -EIO;
90
91 dprintk(1, "%s(): returns 0\n", __func__);
92 return 0;
93 }
94
95 /* dev, reg + first byte */
96 addr = (msg->addr << 25) | msg->buf[0];
97 wdata = msg->buf[0];
98
99 ctrl = bus->i2c_period | (1 << 12) | (1 << 2);
100
101 if (msg->len > 1)
102 ctrl |= I2C_NOSTOP | I2C_EXTEND;
103 else if (joined_rlen)
104 ctrl |= I2C_NOSTOP;
105
106 cx_write(bus->reg_addr, addr);
107 cx_write(bus->reg_wdata, wdata);
108 cx_write(bus->reg_ctrl, ctrl);
109
110 retval = i2c_wait_done(i2c_adap);
111 if (retval < 0)
112 goto err;
113
114 if (retval == 0)
115 goto eio;
116
117 if (i2c_debug) {
118 if (!(ctrl & I2C_NOSTOP))
119 printk(" >\n");
120 }
121
122 for (cnt = 1; cnt < msg->len; cnt++) {
123 /* following bytes */
124 wdata = msg->buf[cnt];
125 ctrl = bus->i2c_period | (1 << 12) | (1 << 2);
126
127 if (cnt < msg->len - 1)
128 ctrl |= I2C_NOSTOP | I2C_EXTEND;
129 else if (joined_rlen)
130 ctrl |= I2C_NOSTOP;
131
132 cx_write(bus->reg_addr, addr);
133 cx_write(bus->reg_wdata, wdata);
134 cx_write(bus->reg_ctrl, ctrl);
135
136 retval = i2c_wait_done(i2c_adap);
137 if (retval < 0)
138 goto err;
139
140 if (retval == 0)
141 goto eio;
142
143 if (i2c_debug) {
144 dprintk(1, " %02x", msg->buf[cnt]);
145 if (!(ctrl & I2C_NOSTOP))
146 dprintk(1, " >\n");
147 }
148 }
149
150 return msg->len;
151
152eio:
153 retval = -EIO;
154err:
155 if (i2c_debug)
156 pr_err(" ERR: %d\n", retval);
157 return retval;
158}
159
160static int i2c_readbytes(struct i2c_adapter *i2c_adap,
161 const struct i2c_msg *msg, int joined)
162{
163 struct cx25821_i2c *bus = i2c_adap->algo_data;
164 struct cx25821_dev *dev = bus->dev;
165 u32 ctrl, cnt;
166 int retval;
167
168 if (i2c_debug && !joined)
169 dprintk(1, "6-%s(msg->len=%d)\n", __func__, msg->len);
170
171 /* Deal with i2c probe functions with zero payload */
172 if (msg->len == 0) {
173 cx_write(bus->reg_addr, msg->addr << 25);
174 cx_write(bus->reg_ctrl, bus->i2c_period | (1 << 2) | 1);
175 if (!i2c_wait_done(i2c_adap))
176 return -EIO;
177 if (!i2c_slave_did_ack(i2c_adap))
178 return -EIO;
179
180 dprintk(1, "%s(): returns 0\n", __func__);
181 return 0;
182 }
183
184 if (i2c_debug) {
185 if (joined)
186 dprintk(1, " R");
187 else
188 dprintk(1, " <R %02x", (msg->addr << 1) + 1);
189 }
190
191 for (cnt = 0; cnt < msg->len; cnt++) {
192
193 ctrl = bus->i2c_period | (1 << 12) | (1 << 2) | 1;
194
195 if (cnt < msg->len - 1)
196 ctrl |= I2C_NOSTOP | I2C_EXTEND;
197
198 cx_write(bus->reg_addr, msg->addr << 25);
199 cx_write(bus->reg_ctrl, ctrl);
200
201 retval = i2c_wait_done(i2c_adap);
202 if (retval < 0)
203 goto err;
204 if (retval == 0)
205 goto eio;
206 msg->buf[cnt] = cx_read(bus->reg_rdata) & 0xff;
207
208 if (i2c_debug) {
209 dprintk(1, " %02x", msg->buf[cnt]);
210 if (!(ctrl & I2C_NOSTOP))
211 dprintk(1, " >\n");
212 }
213 }
214
215 return msg->len;
216eio:
217 retval = -EIO;
218err:
219 if (i2c_debug)
220 pr_err(" ERR: %d\n", retval);
221 return retval;
222}
223
224static int i2c_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
225{
226 struct cx25821_i2c *bus = i2c_adap->algo_data;
227 struct cx25821_dev *dev = bus->dev;
228 int i, retval = 0;
229
230 dprintk(1, "%s(num = %d)\n", __func__, num);
231
232 for (i = 0; i < num; i++) {
233 dprintk(1, "%s(num = %d) addr = 0x%02x len = 0x%x\n",
234 __func__, num, msgs[i].addr, msgs[i].len);
235
236 if (msgs[i].flags & I2C_M_RD) {
237 /* read */
238 retval = i2c_readbytes(i2c_adap, msg: &msgs[i], joined: 0);
239 } else if (i + 1 < num && (msgs[i + 1].flags & I2C_M_RD) &&
240 msgs[i].addr == msgs[i + 1].addr) {
241 /* write then read from same address */
242 retval = i2c_sendbytes(i2c_adap, msg: &msgs[i],
243 joined_rlen: msgs[i + 1].len);
244
245 if (retval < 0)
246 goto err;
247 i++;
248 retval = i2c_readbytes(i2c_adap, msg: &msgs[i], joined: 1);
249 } else {
250 /* write */
251 retval = i2c_sendbytes(i2c_adap, msg: &msgs[i], joined_rlen: 0);
252 }
253
254 if (retval < 0)
255 goto err;
256 }
257 return num;
258
259err:
260 return retval;
261}
262
263
264static u32 cx25821_functionality(struct i2c_adapter *adap)
265{
266 return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C | I2C_FUNC_SMBUS_WORD_DATA |
267 I2C_FUNC_SMBUS_READ_WORD_DATA | I2C_FUNC_SMBUS_WRITE_WORD_DATA;
268}
269
270static const struct i2c_algorithm cx25821_i2c_algo_template = {
271 .master_xfer = i2c_xfer,
272 .functionality = cx25821_functionality,
273#ifdef NEED_ALGO_CONTROL
274 .algo_control = dummy_algo_control,
275#endif
276};
277
278static const struct i2c_adapter cx25821_i2c_adap_template = {
279 .name = "cx25821",
280 .owner = THIS_MODULE,
281 .algo = &cx25821_i2c_algo_template,
282};
283
284static const struct i2c_client cx25821_i2c_client_template = {
285 .name = "cx25821 internal",
286};
287
288/* init + register i2c adapter */
289int cx25821_i2c_register(struct cx25821_i2c *bus)
290{
291 struct cx25821_dev *dev = bus->dev;
292
293 dprintk(1, "%s(bus = %d)\n", __func__, bus->nr);
294
295 bus->i2c_adap = cx25821_i2c_adap_template;
296 bus->i2c_client = cx25821_i2c_client_template;
297 bus->i2c_adap.dev.parent = &dev->pci->dev;
298
299 strscpy(bus->i2c_adap.name, bus->dev->name, sizeof(bus->i2c_adap.name));
300
301 bus->i2c_adap.algo_data = bus;
302 i2c_set_adapdata(adap: &bus->i2c_adap, data: &dev->v4l2_dev);
303 i2c_add_adapter(adap: &bus->i2c_adap);
304
305 bus->i2c_client.adapter = &bus->i2c_adap;
306
307 /* set up the I2c */
308 bus->i2c_client.addr = (0x88 >> 1);
309
310 return bus->i2c_rc;
311}
312
313int cx25821_i2c_unregister(struct cx25821_i2c *bus)
314{
315 i2c_del_adapter(adap: &bus->i2c_adap);
316 return 0;
317}
318
319#if 0 /* Currently unused */
320static void cx25821_av_clk(struct cx25821_dev *dev, int enable)
321{
322 /* write 0 to bus 2 addr 0x144 via i2x_xfer() */
323 char buffer[3];
324 struct i2c_msg msg;
325 dprintk(1, "%s(enabled = %d)\n", __func__, enable);
326
327 /* Register 0x144 */
328 buffer[0] = 0x01;
329 buffer[1] = 0x44;
330 if (enable == 1)
331 buffer[2] = 0x05;
332 else
333 buffer[2] = 0x00;
334
335 msg.addr = 0x44;
336 msg.flags = I2C_M_TEN;
337 msg.len = 3;
338 msg.buf = buffer;
339
340 i2c_xfer(&dev->i2c_bus[0].i2c_adap, &msg, 1);
341}
342#endif
343
344int cx25821_i2c_read(struct cx25821_i2c *bus, u16 reg_addr, int *value)
345{
346 struct i2c_client *client = &bus->i2c_client;
347 int v = 0;
348 u8 addr[2] = { 0, 0 };
349 u8 buf[4] = { 0, 0, 0, 0 };
350
351 struct i2c_msg msgs[2] = {
352 {
353 .addr = client->addr,
354 .flags = 0,
355 .len = 2,
356 .buf = addr,
357 }, {
358 .addr = client->addr,
359 .flags = I2C_M_RD,
360 .len = 4,
361 .buf = buf,
362 }
363 };
364
365 addr[0] = (reg_addr >> 8);
366 addr[1] = (reg_addr & 0xff);
367 msgs[0].addr = 0x44;
368 msgs[1].addr = 0x44;
369
370 i2c_xfer(i2c_adap: client->adapter, msgs, num: 2);
371
372 v = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
373 *value = v;
374
375 return v;
376}
377
378int cx25821_i2c_write(struct cx25821_i2c *bus, u16 reg_addr, int value)
379{
380 struct i2c_client *client = &bus->i2c_client;
381 int retval = 0;
382 u8 buf[6] = { 0, 0, 0, 0, 0, 0 };
383
384 struct i2c_msg msgs[1] = {
385 {
386 .addr = client->addr,
387 .flags = 0,
388 .len = 6,
389 .buf = buf,
390 }
391 };
392
393 buf[0] = reg_addr >> 8;
394 buf[1] = reg_addr & 0xff;
395 buf[5] = (value >> 24) & 0xff;
396 buf[4] = (value >> 16) & 0xff;
397 buf[3] = (value >> 8) & 0xff;
398 buf[2] = value & 0xff;
399 client->flags = 0;
400 msgs[0].addr = 0x44;
401
402 retval = i2c_xfer(i2c_adap: client->adapter, msgs, num: 1);
403
404 return retval;
405}
406

source code of linux/drivers/media/pci/cx25821/cx25821-i2c.c